We actually tried making this in our shop using his PCB, and it doesn't work. There are quite a few things missing in this write up. Several components for the PCB are not listed... such as the resistors values...

Fun tip if you don't want to do design work, just go onto Thingiverse and make a custom Key Chain with text. Then in the 3D printing software mirror the image. It makes things very quick and easy for those who don't want to mess with 3D design work. I recently did that for something my wife was working on.

We redesigned this project to use a custom Arduino Shield because of this exact problem. Doing a custom shield and sensor holder also allowed up to remove most of the weird wiring, which cut down on our tech support. We should really post those...

Kudos! Thats a great write up and a lot of good information for newbies!Keep up the good work. I remember literally driving myself bonkers 8 years ago trying to do this exact same circuit on a breadboard. I wish I would have had your directions.

Wait... what? Your comment doesn't make a lot of sense. Yes, he's using standard off the shelf parts... but no one is going to build all these electronics parts from scratch (like who seriously builds their own servos?!?!). This is a solid project and a solid write up.

KISELIN has the right idea. The sensors are one of the cheapest parts of this project. There are not many ways to reduce the cost of this project, minus the obvious of not building the watt meter.

No. Not at all. If you threw a resistor into the mix between your speaker and the rest of the circuit, that could be why. I threw in a variable resistor in order to control volume since it was TOO loud.

Don't use this kit for a Science Fair Project. You're not collecting data or getting any meaningful information from it. You can't ask a good question. (As a former middle school science teacher, thats my advice.)

Drilling them out was a bad idea, it killed the pass through connection and the stepper motor doesn't work. You should update your PCB since the holes for the Stepper Driver don't work. Maybe drilling them out but soldering both top AND bottom would work, but otherwise this makes using a stepper driver nearly impossible with the current PCB design.

Using a 9V battery to charge a cell phone is a great way to spend a fortune on 9V batteries and still not have any charge on your phone. 9V batteries have a very low amount of amperage and won't charge a phone more than 1-2%. This is why everyone is using those $5 USB power banks. They will give you half a charge or better (for the small ones) and are rechargeable. And cheap. And rechargeable. Using a 9V battery "works" in the same way that swimming across the Atlantic "works", but anyone with common sense would just take a boat.

I noticed that when we got the PCBs made up, the holes for the Stepper Driver were smaller than all the others and our pins didn't fit through. (We used OSH Park, and they're usually spot on.) We were able to drill them out and get things working, but you should check the files on your end.

I mean, our products are 100% Open Source, and we're even using someone else's code (which we did ask permission to use). However I find it annoying when people reuse our graphics, diagrams, and laser cut files. This isn't the first time we've had this happen to us before, it's just kind of sad.

I'm torn. On one hand I'm glad you liked our original Dual Axis Tracker project, on the other hand I don't like the fact that your instructable is made up of 90% our written text, line art, code, and even some of our original pictures (hello shots of my thumb). Really, Step 14 is the only "new" stuff you added to your project. Not cool man.

Nooooooo. 9V batteries have a high voltage but a low amperage. If you're looking at trading a 9V battery for a 5% phone charge, go for it. Or do what everyone else does and just buy a $10 rechargeable USB Power Bank on amazon which will give you a 100% phone charge. This project "works" but not in any useful way.